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Stirling Engine Powered Bicycle

07/09/2009 11:18 AM

Shortage of oil, coupled with increased demands as countries such as China, India, Russia and their emerging-market economies industrialise has significantly influenced supply and demand in the oil industry. Furthermore, their consumers, with rising incomes, are developing an appetite for personal transport and other energy-consuming machinery. Consequently, the demand for oil based on present consumption trends will increase considerably. Furthermore, the world population could increase by a couple of billion people over the next 20 to 25 years, resulting in even greater demand for oil, unless we come up with alternative sources of energy.

Also as we enter an era where demand for oil cannot be satisfied we need to consider finding alternative ways of providing energy and power. Moreover, combustion of oil contributes significantly to environmental pollution.

From the point of view of personal transport we could consider an alternative propulsion method. I thought that it would be interesting and fun to design and build a Stirling engine powered bicycle. However, the project will involve serious engineering analysis including heat transfer, thermodynamics, structural analysis, vehicle dynamics, together with human factors engineering.

In looking at previous and current attempts to build a bike powered by a Stirling engine I've only come up with the following.

Nathanael Greene Herreshoff – Stirling Powered Motorcycle

Nathanael Herreshoff was a Naval Architect who was born in 1848 in Bristol, Rhode Island, USA. In 1872 he built a bicycle powered by a Stirling Engine. The machine's wheels were 28 inches in diameter. The engine powered the rear wheel. I have no further details.

Andy Ross's Stirling Engine Powered Bicycles

In his book "Making Stirling Engines" Andy Ross shows two installations of Stirling engines to power a bicycle. One with a C-60 engine fitted and the other with a D-90. Both engines were designed and built by Andy.

Dean Kamen's Stirling Hybrid Scooter

Dean Kamen, inventor of the Segway, continues to invent new types of transportation. The latest is a hybrid electric scooter that uses a Stirling engine to partially recharge its battery pack.

Kamen's patent states that the invention is a conventional scooter with a Stirling engine and fuel tank under the seat, a rechargeable battery pack in the floor, and a radiator in the front. The Stirling engine has a low energy output on its own, but it could supply power when the bike is at a standstill, making sure that the battery is fully charged.

I'm looking at using an engine with maximum power of 1 hp (about 750 W). I don't want to add the complexity of driving a generator to subsequently power an electric motor to propel the bike. Hence I plan a mechanical transmission which will need stepping down to drive the bicycle wheel. I do not fancy heat under my legs so will possibly look to installing the engine and associated systems in a sidecar which will be clamped to the bike. The Stirling engine will power the sidecar wheel which will propel the bike. I'm aware that it's difficult to steer a sidecar combination so I plan on having the sidecar wheel mounted quite close to the bicycle. The alternative configuration is in fact to use an adult tricycle and install the engine etc behind the rider.

Re: Stirling Engine Powered Bicycle

07/09/2009 12:18 PM

Hi,

Thanks for the questions.

There are regulatory requirements with respect to building such a machine. It has to be inspected By Department of Transport engineers when built to ensure that it is safe and roadworthy. If it was powered by steam road tax is not required but insurance is a must. An MOT test? - uncertain about the requirement at the moment. However, part of the design work involves a full understanding of regulatory requirements. The Governent has a detailed set of regulations covering 'one off' designs for use as transport on public roads. I have seen Steam powered vehicles mentioned in the regulations but nothing about Stirling powered vehicles.

I have been involved in a similar project for a steam-powered bicycle. I surveyed past and present machines and found well over a 100; most were from the USA and UK. I have a reasonable understanding of the regulatory requirements for the steam vehicle. However, my survey of bicycles powered by Stirling engines has produced a total of 4, three of those from the USA. Consequently questions posed to the Department of transport will be against a little known mode of propulsion, albeit that it is safer than steam.

Regarding the crash helmet issue. I for one wil be wearing one. However, in looking at steam powered bicycles all photos that I've seen of riders of such machines show them without crash helmets. Neverthe less I will be checking legal requirements.

Re: Stirling Engine Powered Bicycle

Okay.. Are we talking the Stirling to heat water to steam or to somehow convert air into energy? Stirling engine in itself is a term for a heat trasnfer engine...

We have found that the power solution is not in technology, but in engineering.

I could see a better use of the Stirling design to encompass pressure and hydraulics from the seat, wheels, torq of the bicycle frame, etc to push the pistons. After that, we'd need to change the name of the engine! Just my viewpoint and I would love to see a stirling that functions enough to propel a bicycle. When you complete a project, please share the build up!

Re: Stirling Engine Powered Bicycle

Forget the steam issue. I used that to elaborate on answers to the earlier questions.

The aim is to use a Stirling engine onlty to power the bicycle, simialr to Andy Ross's approach.

Power needed? About 1/2 hp (325 watts), possibly a bit more to accommodate the weight of the engine. So let's aim for 1 hp (approx 750 W). In logging into to various forums a number of people have said that they have bulit engines capable of delivering 1 hp. It might be a sizeable engine, hence the possibility of mounting it in a sidecar, similar to the Smith Motor Wheel in 1910 (see http://www.users.globalnet.co.uk/~pattle/nacc/arc0465.htm) or in an adult tricycle behind the rider.

Re: Stirling Engine Powered Bicycle

Re: Stirling Engine Powered Bicycle

07/10/2009 2:55 PM

I appreciate the humour, however I understood that the horse comes ready made! However, I would appreciate a sincere input. Whilst the engineering part hopefully will be fun it has a serious side to it, trying to help transport issues in developing nations.

Re: Stirling Engine Powered Bicycle

Re: Stirling Engine Powered Bicycle

07/11/2009 1:35 AM

Hi

Heat Source? Anything that can supply heat. Propane, Butane, Bio, woodgas. Yet to to be decided. In developed countries probably propane or butane. In underdeveloped countries possibly woodgas or bio. The quantity of heat available and temperature that can be achieved will determine the source.

A logical step in this project is to examine renewable fuels, e.g. bio fuels produced from vegetable matter. Such fuels are quite environmentally friendly. The fuels may well herald future industries of bio fuel farming and engine manufacture, the latter powering machinery such as electricity generators, pumps and vehicles.

Re: Stirling Engine Powered Bicycle

07/11/2009 11:08 AM

A logical step in this project is to examine renewable fuels, e.g. bio fuels produced from vegetable matter. Such fuels are quite environmentally friendly. The fuels may well herald future industries of bio fuel farming and engine manufacture, the latter powering machinery such as electricity generators, pumps and vehicles.

Why aren't you starting with stationary applications? Sterlings don't exactly have favorable power to weight ratios Why not crawl before running....

Re: Stirling Engine Powered Bicycle

07/11/2009 12:55 PM

Hi

Thanks for the query.

Quite a few people have successfully addressed the stationary applications. Robert Stirling himself, Ericsson, Philips (Holland), William Beale, Merick Lockwood, WhisperGen, a number of European companies just to name a handful. The Japanese are also developing stationary applications. The USA has applied the technology to artificial hearts, NASA to power space systems.

Some companies have developed Stirling engines for marine installations. United Stirling (Sweden) and General Motors to name but two. James Stirling installed one in a ship called the "Highland Lad" in Glasgow built in 1827; the engine provided 20 hp. In 1957 a 40 hp engine was fitted to the Dutch Yacht 'Johan de Witt'. NASA and the US military have carried out extensive research into applying Stirling engine technology in Automotives. Stirling engines have been tried in powering buses. A few enthusiasts in UK, USA and Australia have designed, built and fitted Stirling engines to boats – (UK: Norris Bomford, Malcolm Rowney, Julian Wood; USA: Jim Tangeman; Australia: Harry Diers). So there has been and is quite a lot of work involving non-stationary applications.

However, I have found just a handful of applications for bicycles and small vehicles. A Stirling powered motorcycle was built by Nathanael Herreshoff (a Naval Architect who was born in 1848 in Bristol, Rhode Island, USA). In 1872 he built a bicycle powered by a Stirling Engine. Andy Ross, in his book "Making Stirling Engines", shows two installations of Stirling engines that he designed and built to power a bicycle. The final one is Dean Kamen's Stirling proposed system to propel a Hybrid Scooter. So we have only a small focus on Stirling engines needed for small vehicles.

Another area of interest is that of looking to help developing nations achieve self sufficiency. A vehicle powered by a Stirling engine leads to something quite serious that complements the self sufficiency ideas, a Basic Utility Vehicle (BUV) for construction and use in developing countries. The idea is to design and build a rugged, simple vehicle that can carry in the order of 1,000 pounds of cargo using off the shelf parts for a cost of about £700 (say aboout $1,500). The vehicle is designed for slow speeds and rural roads in these countries. In addition, the vehicle's engine has to be capable of powering portable accessories such as generators, pumps and compressors (that covers stationary applications). The idea is well advanced in the USA with an annual inter-university competition aimed at BUV design and construction. However, competition designs seem to focus on internal combustion (IC) engines whereas I want to concentrate on a Stirling engine on the basis that all sorts of things can be burnt to provide heat. Furthermore, gasoline and diesel can be prohibitively expensive to many inhabitants of poorer countries.

So I aim to start reasonably small with powering a bicycle. After that it seems logical to progress to the BUV. I ad considered a steam engine to power the BUV but such a device has high water consumption; not necessarily readily available in certain developing nations.

One of Andy Ross's engines used to power a bicycle produced 104 Watts and weighed 3.4 Kg, about 7 lbs or so. The power is a low for that needed to propel a bicycle. A German built engine, the ST 05 G Stirling Engine, produces 300 to 500 Watts. I've yet to find the weight. It certainly looks larger than the Ross engine. ST 05 G bore (working piston is just over 3 inches with stroke at 3 inches, for Ross's machine bore is just over 2 inches, stroke less than one inch). However, I'm looking at possibly mounting the engine in a sidecar, similar to the Smith Motor Wheel installation in 1910 (see http://www.users.globalnet.co.uk/~pattle/nacc/arc0465.htm)

Japanese schools and academic institutes are heavily involved in studying the Stirling engine albeit I cannot find any reference to installations for bikes or autos. They are certainly addressing stationary power generators and marine installations.

A little long-winded response I admit. However, lots of studies have focused using on stationary applications, few on the common bicycle. Hence my interest.

Re: Stirling Engine Powered Bicycle

07/13/2009 1:40 AM

Thanks Garthh. Striling engines are fascinating. I have collected material over a few years. I'm an aeronautical engineer and whilst I knew of the engines I knew very little about them. I was looking for something that my first year students at university could readily capture in their minds when I came across an article about Robert Stirling. That did it, I was hooked. I then move on with the topic to my second yaer students. My third year ones wanted to use the idea for their projects. We had some fun and they all learnt a lot about thermodynamics amongst other things.